Subject: [Sigtran] M3UA-v02 Last Call Comment: ASP Active procedures management blocking.

From: "Brian F. G. Bidulock" <[email-masked]>
Date: Sat, 8 May 2004 02:16:03 -0600

New ASP active procedure text conflicts with ASP active management blocking
procedures.  The offending text is:

|   - If the RC parameter is included in the ASP Active message and the
|     corresponding RK has been previously defined (by either static
|     configuration or dynamic registration), the peer node MUST respond
|     with an ASP Active Ack message if it is ready to handle traffic;
|     otherwise it will not respond (meaning that it is not ready to
|     become active). This is valid for either: ASP was in ASP-ACTIVE or
|     ASP-INACTIVE states.

Per section 3.8.1 it was always the intent that if an SGP could not activate
an ASP for an AS because it was unable to handle traffic for that AS, that
it respond with ERR("Refused - Management Blocking").  The pertinent text in
section 3.8.1 is as follows:

   The "Refused - Management Blocking" error is sent when an ASP Up or
   ASP Active message is received and the request is refused for
   management reasons (e.g., management lockout").  If this error is in
   response to an ASP Active message, the Routing Context(s) in the ASP
   Active message SHOULD be included in the Error message.

The new text seems to imply that the ASP Active Ack message should be
withheld.  That is a bad thing, as it will cause the ASP to resend the ASP
Active message indefinitely.

Reword the offending text as:

>   - If the RC parameter is included in the ASP Active message and the
>     corresponding RK has been previously defined (by either static
>     configuration or dynamic registration), the peer node MUST respond
>     with an ASP Active Ack message.

And add at the bottom:

>   If for any local reason (e.g., management lockout) the SGP cannot
>   respond with an ASP Active Ack message, the SGP responds to an ASP
>   Active message with an Error message with reason "Refused -
>   Management Blocking".

This is important: without this procedure, the unsolicited ASP Inactive
Ack cannot work properly.  Unsolicited ASP Inactive Ack works by having
the SGP send an ASP Inactive Ack to an active ASP for which it is no
longer able to process traffic.  When the ASP responds per the ASP
Inactive procedures with an ASP Active message, the SGP responds with
Error("Refused - Management Blocking").  The ASP can then inform local
management and knows that it may have to wait for a longer interval
or may require operator intravention before retesting with another ASP
Active message.

--brian

-- 
Brian F. G. Bidulock    ¦ The reasonable man adapts himself to the ¦
[email-masked]    ¦ world; the unreasonable one persists in  ¦
http://www.openss7.org/ ¦ trying  to adapt the  world  to himself. ¦
                        ¦ Therefore  all  progress  depends on the ¦
                        ¦ unreasonable man. -- George Bernard Shaw ¦

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